Title: The Micro Harmonic Drive gear - Micromotion

21.11.2006
to convert the very high rotational speeds of up to 100.000 rpm and very low
output torques in a range of some µNm provided by current micromotors into
lower speeds and higher torques as required by real applications in industrial
machines and equipment. The gear is manufactured by a special production
process, called “Direct-LIG”, by which the individual gear components are
formed galvanically in a 3-dimensional mould produced in a photoresist using
X-ray lithography. This production process has been continuously improved to
allow the cost effective manufacture of metallic microgears in small to
medium series production.
The gear principle is based on the well-known Harmonic Drive ® principle, used
in the successful “macro-technologically” manufactured reduction gears of
the same name. A major difference of the microgear is the use of a planetary
gear to provide an initial speed reduction within the space envelope of the
Harmonic Drive ® gear stage. This planetary stage is provided with radially
deformable planet gears, in order to avoid backlash in this reduction stage.
The advantages of miniaturization, e.g. low masses, low power consumption
and small dimensions open new fields of applications for powerful micro
actuators in dynamically growing markets. Innovative fields for micro gear
motors arises e.g. in medicine, aerospace, automated assembly and consumer
industry. In addition to their miniaturized size and low weight micro gear
systems must also feature zero backlash and precise angular transmission.
With a repeatability and lost motion of less than 10 arcseconds the Micro
Harmonic Drive ® is ideally suited for applications in high precision micro
positioning drive systems. This unique micro gear is also the basis for the
world’s smallest backlash free servo actuator, developed in cooperation with
Maxon Motor AG of Switzerland.
Since its market introduction in 2001 the Micro Harmonic Drive ® has
successfully made the transition from laboratory into industrial applications
(see Figure 1.2). The micro gears and micro actuators are already successfully
used in micro-robots, semiconductor manufacturing equipment and even in
spacecraft.
Erstellt von Reinhard Degen Micro Harmonic Drive5.doc Seite 3 von 44